Angular momentum-dependent topological transport and its experimental realization using a transmission line network

TL;DR

This paper demonstrates a new way to realize topological transport in classical waves using angular momentum, experimentally showing one-way edge states in a transmission line network, inspired by quantum spin Hall effects.

Contribution

It introduces a novel mechanism based on angular momentum-orbital coupling to achieve topological phases in classical wave systems, supported by experimental validation.

Findings

Experimental observation of one-way topological edge states in a small network

Local Chern numbers describe edge state properties

Angular momentum can replace pseudo-spins for topological effects

Abstract

Novel classical wave phenomenon analogs of the quantum spin Hall effect are mostly based on the construction of pseudo-spins. Here we show that the non-trivial topology of a system can also be realized using orbital angular momentum through angular-momentum-orbital coupling. The idea is illustrated with a tight-binding model and experimentally demonstrated with a transmission line network. We show experimentally that even a very small network cluster exhibits one-way topological edge states, and their properties can be described in terms of local Chern numbers. Our work provides a new mechanism to realize counterparts of the quantum spin Hall effect in classical waves and may offer insights for other systems.